week 4 low polygon modelling

Business and Computing Deanery

3D Modelling Tools

Week 4 Low polygon modelling

3D Modelling Tools 2

From previous week The importance of lining things up

Snaps, grid, align Cloning Arrays Grouping Modifiers


This week Low polygon modelling Working with sub-objects

Collect portfolio 1


Editable objects Do not have the same flexibility of

parameters They deal with sub-objects and

editing functions Editable objects include:

Meshes Polygons Patch Splines Murdock K.L., (2005)


Editable objects Are not created They are converted from another

object, usually a primitive Loose their parametric properties

after they have been converted Edit sub-objects

Edges Vertices Faces

Murdock K.L. (2005)


Surface Modeling Surface modeling is more free form

than geometric (parametric) modeling

Use the modifier stack to “collapse” a parametric model to some form of editable surface

Once you have done so, a variety of tools let you shape the surface

3ds max v7


Modeller concepts Types of modelling systems:

Parametric Mesh Polygon Spline Patch

Many 3D modelling tools combine two or more of these basic techniques Giambruno M, (2002)


Parametric modellers Retain their base geometric

information Default shape Current size Segments

This information can be accessed and altered

Can be spline or polygon based

Deformations can be applied


Polygon modellers Objects constructed

with polygons Made up of tiny, flat

surfaces More polygons

mean More detail Bigger file sizes

Low polygon Used in real-time

games Small file sizes Quick to render

3ds max v7


Polygons Objects composed of faces An editable poly is a polygonal mesh

Unlike an editable mesh, it uses more than three-sided polygons

Five sub-object levels Vertex Edge Border Polygon Element


Meshes A mesh object made up of triangular

faces as an object and at three sub-object levels Vertex Edge Face

Faces are smoothed together when rendered


Spline modellers A line defined as points, usually

curved Resolution independent

No faces Useful for creating organic shapes Different types

B-spline Bezier NURBS

Non-uniform rational b-splinesGiambruno M, (2002)


Spline types B-spline Bezier NURBS

More information at http://www.doc.ic.ac.uk/~dfg/AndysSplineTutorial

3D Graphics and animation


Patch modellers Use a network of control

points Lattice of splines or

polygons Stretch or tug on the

shape Useful for organic forms

3ds max v7


Mesh or poly - which to use?History lesson Initially Max only supported mesh

objects Subdividing the mesh into triangular faces

ensured that all faces were coplanar Guaranteed to render well

Over time rendering engines have been modified to handle polygons Makes the model more efficient Eliminates all the extra edges required to

triangulate the mesh Murdock K.L. (2005)


Why do I want to count them?

Which to use? Check with your game engine

Some still require that all faces be coplanar

Working with polygon is quicker More advanced editing features with

Max Polygon count feature

Sometimes the terms are interchanged!!!


Converting to editable objects Use the Quad

menu Or

Right click the object in the Modifier Stack

3ds max v7


Converting to editable objects If a modifier has been applied to an object

you need to use the Collapse All command first Combines the stack operations Cannot undo, save a backup file

You can convert between different types but each conversion may subdivide the object

You can apply a modifier to convert an object Retains the parametric qualities of the object, but

you cannot edit the mesh


Editable Mesh Surface Polygon mesh

3ds max v7


Working with sub-objects Insert a vertex Multiple selection

Control + click Draw a lasso Select region

3ds max v7


Edit face A face is the smallest possible mesh

object A polygon formed by three vertices

Faces provide the renderable surface of an object

3ds max v7


Extrude Extrude Bevel

3ds max v7


Cut Sub-divide a mesh Create another edge Useful to use snap To start from a different

point, right-click To finish cutting, right-click

twice


Bridge Bridging two elements makes them

contiguous, combining them into a single element

3ds max v7


Activity Make a crown

Create a tube Convert to an editable poly Extrude polygons

Try bridging some polygons


Soft selection The Soft Selection

controls allow you to partially select sub-objects in the vicinity of an explicit selection

This causes the explicit selection to behave as if surrounded by a "magnetic field"

3ds max v7


Working with vertices Select one or more vertices Magnetic of soft selection

Use for transforms of vertices The program applies a spline curve

deformation to unselected vertices surrounding the transformed selected sub-object

A magnet-like effect with a sphere of influence around the transformation

3ds max v7


Activity Make a face

Create a sphere Convert to a polygon Push and pull vertices to make a face

using soft selection Not easy!


Edit Edge An edge is a line,

visible or invisible, forming the side of a face and connecting two vertices

Two faces can share a single edge


Poly counts Total number of polygons that make

up a given object 3D rendering engines have limits Software has a Polygon Counter

utility You can set a budget for selected

objects


Low polygon modelling What happens to a game if the

polycount in a model is too high? Too slow to play May crash the system

Overlapping meshes or undeleted faces may affect the appearance

Planning of low polygon models is important


Spec-ing a low polygon model File format Number and type of polygons Use of texture maps

Particular type? Colour depth? Specific size? Transparency?

Examine any sample models


Portfolio 2 Repeat a much as possible of Portfolio 1 using

low polygon modelling techniques Count the polygons, record the number on your

paper submission

Screen grab of 3ds max of your model of: A room created from primitives

Floor 3 walls

Containing a table Rectangular table top Four rectangular legs

Plus three chairs or stools


Next week Lecture

2D to 3D modelling Storyboards


Impendent study Directed reading 3DS Max 7 Bible

Read Chapter 13 Portfolio 2 Presentation Tutorials

Chess Set


Questions You have been asked to model an

aeroplane for use in a game What do you need to know before you

start modelling Describe the difference between

geometric and surface modelling, which method would you use, justify your choice

Describe the difference between mesh and polygon modelling, which method would you use, justify your choice


References 3ds max v7, (2005) User Reference and

Tutorials Giambruno M, (2002) 3D Graphics &

Animation, 2nd Edition, New Riders, ISBN: 0-7357-1243-3

Kerlow I. V., (2003) The Art of 3-D Computer Animation and Effects , 3rd Edition, John Wiley & Sons Inc; ISBN: 0471430366

Murdock K.L., (2005) 3DS Max 7 Bible, John Wiley & Sons Inc, ISBN: 0764579711

week 4 low polygon modelling

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